Interpreting otoacoustic emissions in humans : evidence for multiple generating mechanisms

Healthy ears generate sounds known as otoacoustic emissions that can be evoked and measured in the ear-canal using small, low-noise microphones. The ability to measure acoustic signals that originate within the cochlea provides noninvasive access to what in humans is an almost inaccessible organ. Although otoacoustic emissions (OAEs) are frequently used as noninvasive probes of cochlear function in both the clinic and the laboratory, their utility is limited by incomplete knowledge of their generating mechanisms. A recently proposed model suggests that most OAEs are mixtures of -emissions arising by two fundamentally different mechanisms: 1) nonlinear distortion induced by cochlear traveling: waves and 2) linear reflection 6f those waves from pre-existing micromechanical impedance perturbations. The model predicts that OAEs generated by wave-induced perturbations manifest a phase that is nearly-frequency invariant whereas OAEs generated by reflection from pre-existing perturbations manifest a phase that rotates rapidly with frequency. The model suggests that the relative contribution from each mechanism to any emission measurement depends on factors such as the type and intensity of the evoking stimulus.

Department dc:contributor.department

Harvard University--MIT Division of Health Sciences and Technology.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2006

Author dc:creator

• Kalluri, Radha

Advisor dc:contributor.advisor

• Christopher A. Shera.

• Harvard University--MIT Division of Health Sciences and Technology.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/35547
• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Identifier URI

http://dspace.mit.edu/handle/1721.1/35547

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/35547